1. Field of the Invention
This invention relates in general to space diversity receivers wherein the useful signals of the two receiving branches are combined in a summing circuit in the IF frequency range and in which an electronically controlled phase corrector is mounted in one of the receiving branches and a phase monitoring circuit is connected at the output of the phase corrector between the two receiving branches with the output signal of the phase monitoring circuit controlling the phase corrector.
2. Description of the Prior Art
In space diversity reception, there is a problem in that the two signals of identical frequencies must be summed in the proper phase. Such summation can occur in the radio frequency, intermediate frequency or base-band frequency stages. Thus, there are RF, IF or BF combiners. If the combination occurs in the radio frequency or intermediate frequency stages, then a variable phase corrector must be used to assure that the phase differences between the two received signals caused due to changing propagation conditions are sufficiently equalized. Thus, it is a problem to provide the so-called infinite phase corrector or goniometer with electronic means and automatic control of the phase corrector.
A radio frequency combiner is discussed in the article entitled "Elektronisches Raumdiversity-System fur Richtfunkanlagen" by U. H. Gysel which was published at the NTG conference for directional radio from Apr. 23 to Apr. 25, 1980, and which paper is dated Apr. 4, 1980.
An IF combiner is discussed in the report entitled "New Generation 6 GHz 1800 Channel/78 Mbits Radio System" by T. Furuya et al which was presented at the European Microwave Conference in 1978.